Conduits for use in placing a target vessel in fluid communication with a source of blood

ABSTRACT

Methods and devices for placing a target vessel in fluid communication with a source of blood and a target vessel. A conduit includes first portion adapted to be placed in fluid communication with a source of blood, such as a heart chamber, and a second portion adapted to be placed in fluid communication with a target vessel having a lumen, such as coronary artery. The first and second conduit portions are transverse to each other such that the conduit is generally T-shaped. The conduit lies on an exterior of the heart between the blood source and the target vessel and is configured to deliver blood in multiple directions into the lumen of the target vessel. For example, in an occluded coronary artery, blood flows both toward and away from the occlusion. The conduit may be flexible, rigid, collapsible or non-collapsible, and may be formed of synthetic vascular graft material, tissue, or a combination of the two. A conduit delivery device is disclosed for deploying the conduit in a target vessel and perfusing the vessel during such deployment.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of application Ser.No. 09/023,492, filed on Feb. 13, 1998 and entitled “Methods and DevicesProviding Transmyocardial Blood Flow to the Arterial Vascular System ofthe Heart,” the entire subject matter of which is incorporated herein byreference. This application is also a continuation-in-part ofapplication Ser. No. 09/232,103, filed on Jan. 15, 1999 and entitled“Methods and Devices for Forming Vascular Anastomoses,” as well asapplication Ser. No. 09/232,062, filed on Jan. 15, 1999 and entitled“Methods and Devices For Bypassing an Obstructed Target Vessel byPlacing the Vessel in Communication with a Heart Chamber ContainingBlood,” the entire subject matter of both applications beingincorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a conduit that is placed in fluidcommunication with a target vessel and a source of blood, and methodsand devices for placing the conduit in fluid communication with thetarget vessel and the source of blood.

[0004] 2. Description of the Background Art

[0005] Despite the considerable advances that have been realized incardiology and cardiovascular surgery, heart disease remains the leadingcause of death throughout much of the world. Coronary artery disease, orarteriosclerosis, is the single leading cause of death in the UnitedStates today. As a result, those in the cardiovascular field continue tosearch for new and improved treatments.

[0006] Coronary artery disease is currently treated by interventionalprocedures such as percutaneous transluminal coronary angioplasty(PTCA), coronary stenting and atherectomy, as well as surgicalprocedures including coronary artery bypass grafting (CABG). The goal ofthese procedures is to reestablish or improve blood flow throughoccluded (or partially occluded) coronary arteries, and is accomplished,for example, by enlarging the blood flow lumen of the artery or forminga bypass that allows blood to circumvent the occlusion. Whatprocedure(s) is used typically depends on the severity and location ofthe blockage(s). When successful, these procedures restore blood flow tomyocardial tissue that had not been sufficiently perfused due to theocclusion.

[0007] An alternative, recently proposed treatment places the targetvessel in fluid communication with a heart chamber containing blood, forexample, the left ventricle. Blood flows from the ventricle into aconduit that is in fluid communication with the target vessel. Some ofthe challenges associated with these procedures include delivering anddeploying the conduit in the patient's body, and in particular properlypositioning the conduit with respect to the heart chamber and the targetvessel, as well as obtaining beneficial flow characteristics through thetarget vessel.

[0008] The improvement and refinement of existing treatments and thesearch for new treatments are indicative of the significant effort thatcontinues to be expended in order to develop better and more efficientways of revascularizing the heart.

[0009] Accordingly, there remains a need in the art for improved methodsand devices that are capable of being used quickly, easily and in arepeatable manner to carry out cardiac revascularization.

SUMMARY OF THE INVENTION

[0010] The invention provides methods and devices for placing a conduitin fluid communication with a source of blood and a target vessel. Onepreferred method according to the invention includes steps of placing aconduit having a lumen in fluid communication with a heart chambercontaining blood, placing the conduit in fluid communication with thelumen of a target vessel and securing the conduit to the target vessel,delivering blood from the heart chamber into the conduit during at leastone phase of the heart cycle, and permitting the blood to flow from theconduit into the lumen of the target vessel in more than one direction.

[0011] Another preferred method is similar to the above-described methodbut includes the additional step of permitting the blood to exit theconduit unrestricted and in more than one direction in the lumen of thetarget vessel.

[0012] Another preferred method includes steps of providing a conduitincluding first and second portions that are disposed transverse to eachother and have lumens in fluid communication, the first conduit portionincluding at least one inlet and the second conduit portion including atleast one outlet. The inlet of the first conduit portion is placed influid communication with a heart chamber containing blood to allow bloodto enter the lumen of the first conduit portion, and the outlet of thesecond conduit portion is placed in fluid communication with the lumenof a target vessel at a selected location in the target vessel to allowblood to flow into the lumen of the target vessel from the secondconduit portion. The second conduit portion is secured to the targetvessel at the selected location while substantially not moving thesecond conduit portion along a longitudinal axis of the target vessel.

[0013] Still another preferred method includes steps of providing aconduit including first and second portions each of which has a lumen,wherein the first and second conduit portions are disposed transverse toeach other with the lumens in fluid communication and the second conduitportion is at least partially collapsible, and placing the lumen of thefirst conduit portion in fluid communication with a heart chambercontaining blood. The second conduit portion is at least partiallycollapsed and positioned within the lumen of a target vessel at aselected location in the target vessel, and is then expanded within thetarget vessel lumen at the selected location to secure the secondconduit portion to the target vessel in fluid communication therewith.

[0014] Yet another preferred method includes steps of determining athickness of the patient's myocardium adjacent a heart chambercontaining blood, placing a conduit having a lumen in the myocardiumwith the lumen of the conduit in fluid communication with the heartchamber containing blood, placing the conduit in fluid communicationwith the lumen of a target vessel and securing the conduit to the targetvessel, and delivering blood from the heart chamber into the conduit andallowing blood to exit the conduit and enter the target vessel in morethan one direction.

[0015] One preferred device constructed according to the inventionincludes a conduit having first and second portions, wherein the firstand second conduit portions each have an axis and a lumen through whichblood may flow, the axes of the first and second conduit portions beingtransverse to each other. The first conduit portion is configured to beplaced in fluid communication with a heart chamber containing blood andincludes at least one inlet configured to be at least partiallypositioned in myocardial tissue without collapsing during myocardialcontraction, whereas the second conduit portion is configured to be atleast partially positioned within the target vessel and includes atleast one outlet adapted to deliver blood to the target vessel. Theinlet of the first conduit portion is more rigid than the outlet of thesecond conduit portion.

[0016] Another preferred device includes a conduit having first andsecond portions that are transverse to each other and have lumens influid communication. The first conduit portion has a longitudinal axisand is sized and configured to be placed in fluid communication with aheart chamber containing blood, and the second conduit portion has alongitudinal axis and is sized and configured to be placed at leastpartially within a target vessel in a patient's vascular system todeliver blood to the target vessel. The second conduit portion has firstand second ends adapted to be positioned in the target vessel, and thelongitudinal axis of the first conduit portion crosses the longitudinalaxis of the second conduit portion at a location that is spaceddifferent distances from the first and second ends of the second conduitportion.

[0017] Another preferred device includes a conduit having first andsecond portions having respective axes that are transverse to eachother, the first conduit portion having a free end configured to beplaced in fluid communication with a heart chamber containing blood, andthe second conduit portion having two free ends that are configured tobe positioned at least partially within the lumen of a target vessel inthe patient's vascular system. The conduit is formed at least in part ofa molded thermoset or thermoplastic material having a predeterminedamount of flexibility to permit the second portion of the conduit to beflexed for placement within the lumen of a target vessel.

[0018] The invention also provides devices and methods for delivering aconduit configured to be placed in fluid communication with a targetvessel and a source of blood. One preferred delivery device includes asupport shaft having a length, and a sheath having a length, a lumen,and a wall with at least one opening extending into the sheath lumen.The support shaft is sized and configured to be at least partiallypositioned in the sheath lumen so as to contact the sheath wall andsubstantially block the opening by preventing communication with thesheath lumen via the opening. The support shaft is movable within thesheath lumen to selectively block or unblock the opening in the sheathwall. A conduit is placed on the sheath and, with the opening unblocked,delivers blood into the sheath lumen for perfusing a vessel into whichthe distal end of the sheath is positioned. As a result, the device maybe used to deliver blood to the tissue during deployment of the conduit,thereby minimizing ischemic time for tissue that heretofore was notperfused while carrying out the procedure.

[0019] Another preferred delivery device is adapted to deliver a conduitfor placing a target vessel in fluid communication with a source ofblood, the conduit including first and second transverse portions eachof which has an axis and a lumen. The first conduit portion includes atleast one inlet configured to be placed in fluid communication with aheart chamber containing blood, and the second conduit portion includesat least one outlet configured to be at least partially positionedwithin the lumen of a target vessel to deliver blood to the targetvessel. The delivery device includes a shaft with a lumen and at leastone opening extending into the lumen, and the second conduit portion ismounted on the shaft. The shaft opening is movable into and out ofalignment with the lumen of the first conduit portion, and is moved intoalignment with the lumen of the first conduit portion to deliver bloodto the shaft lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention will be better understood from the followingdetailed description of preferred embodiments thereof, taken inconjunction with the accompanying drawing figures, wherein:

[0021]FIG. 1 is a front elevation view of a conduit constructedaccording to one embodiment of the invention for placing a source ofblood in fluid communication with a target vessel;

[0022]FIG. 1A is a transverse cross-sectional view taken along line A-Ain FIG. 1;

[0023]FIG. 1B is a plan view of the conduit shown in FIG. 1;

[0024]FIG. 2 is a fragmentary front elevation view of the conduit shownin FIG. 1, wherein a portion of the conduit is removed to expose areinforcing component;

[0025]FIG. 3 is a fragmentary, front elevation view corresponding toFIG. 2 but isolating an alternative embodiment of a reinforcingcomponent;

[0026]FIG. 4 is a front elevation view of a conduit constructedaccording to another embodiment of the invention for placing a source ofblood in fluid communication with a target vessel;

[0027]FIG. 4A is a side elevation view of the conduit shown in FIG. 4;

[0028]FIG. 5 is a front elevation view of a conduit constructedaccording to another embodiment of the invention for placing a source ofblood in fluid communication with a target vessel;

[0029]FIG. 5A is a side elevation view of the conduit shown in FIG. 5;

[0030]FIGS. 6, 7 and 8 are perspective views of conduits constructedaccording to other embodiments of the invention for placing a source ofblood in fluid communication with a target vessel;

[0031]FIG. 8A is a longitudinal cross-sectional view taken through oneend of the conduit shown in FIG. 8;

[0032]FIGS. 9, 10, 11 and 12 are perspective views of conduitsconstructed according to other embodiments of the invention for placinga source of blood in fluid communication with a target vessel;

[0033]FIGS. 13A and 13B are perspective views showing a conduitconstructed according to another embodiment of the invention for placinga source of blood in communication with a target vessel, the conduitbeing shown in its collapsed and expanded orientations, respectively;

[0034]FIGS. 14A and 14B are perspective views showing a conduitconstructed according to still another embodiment of the invention forplacing a source of blood in fluid communication with a target vessel,the conduit being shown in its collapsed and expanded orientations,respectively;

[0035]FIG. 14C is an end elevation view of the conduit shown in FIG.14A;

[0036]FIGS. 15, 16 and 17 are perspective views of conduits constructedaccording to other embodiments of the invention for placing a source ofblood in fluid communication with a target vessel;

[0037]FIGS. 18A and 18B are, respectively, end and side elevation viewsof a conduit constructed according to another embodiment of theinvention;

[0038]FIGS. 19A and 19B are, respectively, end and side elevation viewsof a conduit constructed according to yet another embodiment of theinvention;

[0039]FIG. 20A is a perspective anterior view of a heart and a conduitconstructed according to one embodiment of the invention;

[0040]FIG. 20B is a perspective view of the heart shown in FIG. 20Aafter the conduit has been deployed to carry out a coronary bypassprocedure;

[0041]FIG. 20C is an enlarged sectional view of a portion of the heartshown in FIG. 20B;

[0042]FIGS. 21A and 21B are perspective views of conduits constructedaccording to two embodiments of the invention deployed in a heart tocommunicate a coronary vessel with a heart chamber containing blood;

[0043]FIGS. 22A and 22B are perspective views of conduits constructedaccording to two other embodiments of the invention deployed in a heartto communicate a coronary vessel with a heart chamber containing blood;

[0044]FIG. 23 is a transverse sectional view of a heart showing the leftand right ventricles and several coronary blood vessels;

[0045] FIGS. 24A-24D are elevation views, partly in section,schematically illustrating placement of a conduit in a target vesselaccording to one embodiment of the invention;

[0046] FIGS. 25A-25C are elevation views, partly in section,schematically illustrating placement of a conduit in a target vesselaccording to another embodiment of the invention;

[0047] FIGS. 26A-26C are elevation views, partly in section,schematically illustrating placement of a conduit in a target vesselaccording to yet another embodiment of the invention;

[0048]FIG. 27 is a perspective view of a device constructed according toanother embodiment of the invention for use in perfusing a target vesselwhile introducing a conduit into the vessel;

[0049]FIG. 28 is an exploded perspective view of the device shown inFIG. 27, along with an additional member for sealing the device;

[0050]FIG. 29A is a perspective view of the device shown in FIG. 27 witha conduit mounted thereon;

[0051]FIG. 29B is an enlarged sectional view of the portion encircled inFIG. 29A; and

[0052] FIGS. 30A-30E are elevation views in section schematicallyillustrating the device and conduit shown in FIGS. 29A-29B being used toplace the conduit in fluid communication with the lumen of a targetvessel.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

[0053] The present invention provides a conduit that is placed in apatient's body to establish a flow path between a source of blood and atarget vessel, as well as methods and device for deploying the conduit.In a preferred embodiment, the source of blood is a heart chambercontaining oxygenated blood and the target vessel is a coronary vessel(artery or vein). It will be recognized, however, that the invention maybe used to form a blood flow path between other hollow body structures.Also, as used herein, source of blood refers to any blood-containingstructure, while oxygenated blood refers to blood containing some levelof oxygen.

[0054] The lumen of the target vessel may be partially or completelyobstructed by an occlusion and the conduit placed to form a flow paththat bypasses the occlusion. Alternatively or additionally, the conduitmay be used to create a supplemental blood flow path that feeds into thetarget vessel to augment blood flow (native or other) already present inthe vessel.

[0055] The conduit of the invention may be configured in variousmanners. In its most preferred form, the conduit includes a firstconduit portion having at least one inlet adapted to be placed incommunication with a source of blood and a second portion having atleast one outlet adapted to be placed in communication with the lumen ofa target vessel. The first and second conduit portions may be defined bya single unitary member or several members that are attached or formedinto a desired configuration. The first and second conduit portions aretransverse to each other and have lumens that meet at a junction. Forexample, the first and second conduit portions have respective axes thatextend transversely to each other to form a predetermined angle, theangle preferably being within a desired range that achieves acceptableflow characteristics.

[0056] Referring to FIGS. 1 and 1A-1C, a conduit constructed accordingto one preferred embodiment of the invention is indicated generally bythe reference numeral 10 and includes a first conduit portion 12 and asecond conduit portion 14. The first conduit portion 12 has an inlet 16that is placed in fluid communication with a source of blood, and thesecond conduit portion 14 has a pair of outlets 18 that are placed influid communication with a target vessel. It will be appreciated thatthe first conduit portion 12 may have more than one inlet and the secondconduit portion 14 may have one, two or more outlets. The first andsecond conduit portions 12, 14 have lumens in fluid communication witheach other.

[0057] The illustrated conduit 10 is generally T-shaped with the firstand second conduit portions 12, 14 meeting at a junction 20 such thattheir respective axes a, b are substantially perpendicular. It should benoted, though, that according to the invention the axes a, b of thefirst and second conduit portions 12, 14 could be disposednon-perpendicularly. For example, as discussed further below, ratherthan forming a 90° (or substantially 90°) angle, the axes a, b couldextend transversely to each other to form an acute or obtuse angle(depending on whether the angle is measured from the left or right sideof the axis a, as viewed in FIG. 1).

[0058] The first conduit portion 12 of the illustrated conduit 10 has afree end 22 defining the inlet 16 while the second conduit portion 14has a pair of free ends 24 defining the outlets 18. The free ends 22, 24may be integral extensions of their respective conduit portions or theymay comprise separate members secured to the conduit. One or more of thefree ends 22, 24 may have ends cut, beveled or tapered (or otherwiseconfigured) for easier introduction into the target vessel. The end 24of the conduit portion 14 is preferably formed of a flexible, relativelyatraumatic material (e.g., as discussed below) that will not damage theendothelial cells lining the intimal surface of the target vessel,particularly during placement of the device.

[0059] The inlet 16 or outlets 18 may be located on the conduit 10 at aposition(s) other than those shown in the Figures, e.g., at one or morepoints along the length of the conduit. Similarly, in the illustratedembodiment the first conduit portion 12 (axis a) is offset in that itdoes not bisect the second conduit portion 14 (axis b); this providesthe second conduit portion with different size legs extending away fromthe first conduit portion. Configuring the target vessel portion of theconduit 10 with shorter and longer legs may be useful in introducing theconduit into the target vessel. It should nonetheless be recognized thatthe first conduit portion 12 may be centrally located along the axis bof the second conduit portion 14 to provide legs of equal length, or itmay be offset from the axis b a greater distance than shown in FIG. 1.

[0060] According to a preferred aspect of the invention, the conduit isprovided with a reinforcing component having sufficient strength toensure that the conduit remains open during use by preventing orreducing the likelihood of the conduit kinking or collapsing. Thereinforcing component may be integrally formed with the conduit or itmay comprise a separate member secured thereto. One embodiment of areinforcing component 26 is shown in FIG. 1 (in phantom) and comprises aplurality of coils 28 which extend over the first and second conduitportions 12, 14. See FIG. 2, in which an external portion of the conduit10 is omitted for clarity to expose the reinforcing component 26. Asseen from FIG. 1A, the reinforcing component 26 is preferably encased inthe body of the conduit 10 which prevents contact between blood andtissue and the reinforcing component (coils 28 in this embodiment).

[0061] In the illustrated embodiment, the spacing, as well as the sizeand material of construction, of the coils 28 may be used to determinethe amount of structural support provided by the reinforcing component26. As such, these variables may be selected to produce a conduit havingdesired characteristics. For example, one of the first and secondconduit portions 12, 14 may be made more rigid or flexible than theother by varying the pitch of the coils, the thickness of the wireforming the coils, the material forming the coils, etc., on theportions. Further, the reinforcing component 26 may comprise a singlecoil, a first coil for the first conduit portion and a second coil forthe second conduit portion, a first coil for the first conduit portionand two separate coils for the two free legs of the second conduitportion, etc. Finally, it will be noted that the reinforcing componentmay have a non-coiled configuration, e.g., a stent or stent-likeconstruction, a braided structure, etc., and may comprise one ormultiple members. Exemplary materials include metals or alloys, such astitanium, stainless steel or nitinol, and non-metals, such as polymersor other synthetic materials.

[0062] The second conduit portion 14 is preferably relatively flexibleto allow it to yield slightly when placed in the target vessel andfollow the contour of the target vessel (not shown in FIGS. 1-3). Thefirst conduit portion 12 may be more rigid than the second conduitportion 14, particularly if the blood source is a heart chamber and thefirst conduit portion 12 is placed in (or secured to) myocardial tissue.In this case, the first conduit portion 12 would preferably berelatively rigid to remain open during myocardial contraction. Thejunction 20 of the first and second conduit portions 12, 14 isessentially unreinforced in the embodiment shown in FIGS. 1-2. Thejunction 20 may, however, be made selectively stiff or flexible, e.g.,by disposing one or more coils 28 of the reinforcing component 26 at oradjacent the junction 20, as exemplified by the embodiment shown in FIG.3.

[0063] It will be appreciated that the size of the conduit will varydepending on the application. Referring to FIG. 2, the first conduitportion 12 has a length L1, diameter D1 (or a different dimension if thecross-section is non-circular), while the second conduit portion 14 hasa length L2 and a diameter D2. One or more of these dimensions may bechanged to alter the flow characteristics that the conduit achieves in agiven application, or to modify the conduit for use in differentapplications.

[0064] FIGS. 1-2 depict a conduit that is sized and configured for usein placing a coronary vessel in fluid communication with a heart chambercontaining blood. The distal end of the first conduit portion 12 willpreferably be reinforced by an additional component (not shown in FIGS.1-2, but see element 128 in FIGS. 9-12) that is designed to remain openduring systole once it has been placed in or secured to myocardialtissue. The additional reinforcing component may be positioned over adistal part of the first conduit portion 12 in telescoping fashion, orit may be secured to the end 22 of the first conduit portion 12 andextend axially away therefrom.

[0065] According to another preferred embodiment of the invention, thesecond conduit portion comprises a tubular member that is only partiallyclosed about its circumference, as opposed to a tubular member that isentirely closed about its circumference (as is the embodiment of FIGS.1-3). An exemplary conduit 30 constructed according to this embodimentis shown in FIG. 4 and includes first and second conduit portions 32,34. The conduit 30 is generally T-shaped and may be defined by a singleunitary piece or several discrete pieces of material suitable for use informing a blood flow path, and will be sized depending on the specificapplication, as explained above.

[0066] The first conduit portion 32 has an inlet 36 adapted to be placedin communication with a source of blood, while the second conduitportion 34 has a pair of outlets 38 for directing blood into the targetvessel. The first and second conduit portions 32, 34 meet at a junction40 having a desired amount of flexibility. For example, the firstconduit portion 32 may be more rigid than the second conduit portion 34,while the second conduit portion 34 is more rigid than the junction 40.The first conduit portion has a free end 42 defining the inlet 36, andthe second conduit portion has two free ends 44 defining the outlets 38.The conduit 30 is provided with a reinforcing component 46 includingcoils 48 that essentially correspond to the coils 28 of the reinforcingcomponent 26 described above with respect to the embodiment of FIGS.1-2.

[0067] Referring to FIG. 4A, the second conduit portion 34 extendsthrough an angle θ to form approximately one half of a tubular member (θbeing approximately 180° in the illustrated embodiment). This producesexposed ends or edges E on second conduit portion 34. It will beunderstood that the specific configuration of the conduit including theamount and location of material forming the conduit portions may bevaried, for example, by varying the angle 0 or modifying the profile ofthe edges E of the second conduit portion 34.

[0068]FIG. 4A is a side elevation view of the conduit 30 and illustratesthe relative dimensions of the first and second conduit portions 32, 34,as well as the edges E of the second conduit portion that result fromremoving a section of the tubular element. The coils 48 of theillustrated reinforcing component 46 extend beyond the edges E of thesecond conduit portion 34 and support the target vessel wall around itsentire (or substantially entire) circumference. In this embodiment, thecoils 48 (or other structure of the reinforcing component) extend 360°and, along with the second conduit portion 34, define a complete tubularelement with openings between adjacent coils. The conduit of theinvention may instead have a reinforcing component that supports lessthan the entire circumference of the target vessel wall.

[0069]FIGS. 5 and 5A show a conduit 50 that comprises first and secondconduit portions 52, 54 and has a construction that is essentially thesame as that of the conduit 30. The conduit 50, however, is not providedwith a reinforcing component. As shown in solid lines in FIG. 5A, thesecond conduit portion 54 is the same as the second conduit portion 34of the conduit 30 shown in FIGS. 4 and 4A in that each portion extendsthrough an angle θ to define approximately one half of a tubular member.It should be recognized that the second conduit portion may extend in anangular or circumferential direction more or less than that shown inFIGS. 4A and 5A. For example, FIG. 5A shows (in phantom) a secondconduit portion 56 extending over an angle 4 that is greater than theangle θ, the angle φ being approximately 300°, which is only one exampleof the many possible conduit configurations. As an example, for use intreating coronary vessels, which typically will have a diameter in therange of 1 to 4 mm, the angles θ and φ are preferably in a range of fromabout 90° to 300°, more preferably 90° to 240°, and most preferably 180°to 240°.

[0070] One benefit of the embodiment shown in FIGS. 4-4A and 5-5A isthat a relatively small amount of conduit material must be accommodatedin the target vessel lumen, thereby providing more space to deliverblood. Another benefit is that when the second conduit portion ispositioned within the lumen of a target vessel, a portion of the inner(posterior) wall of the target vessel remains relatively unobstructed bythe conduit. As a result, in the case of a coronary artery as the targetvessel, for example, any septal perforators that lie beneath the conduitremain completely (or substantially) unobstructed to feed blood to themyocardial tissue. Further, any diagonal branches of the vessel thatemanate from an area at (or near) the location of the second conduitportion also would remain unblocked by the conduit. Finally, the partialtubular conduit is flexible and may be used to treat different sizevessels because the edges E of the second conduit portion may bepositioned at various locations along a vessel wall.

[0071] Moreover, this embodiment of the invention is particularly usefulin treating the coronary arteries of patient's suffering fromarteriosclerosis. That is, the inner or posterior wall of a diseasedcoronary artery will typically be covered with stenosis or plaque; as aresult, contacting this area with a device may lead to various problems,such as dislodging stenotic material or damaging any healthy tissue thatstill exists. This embodiment provides conduits that are positionedwithin the lumen of the artery without contacting much of the diseasedinner artery wall.

[0072] This is in contrast to a conduit having a portion thatsubstantially or completely covers the luminal surface of the wall ofthe target vessel, thereby covering the inner vessel wall andrestricting or blocking flow between the vessel and any diagonalbranches or septal perforators. This aspect of the invention isdescribed further in connection with the Figures below which illustrateexemplary methods of using conduits constructed according to theinvention. Nonetheless, the conduit of the invention may be positionedtransmurally if desired.

[0073] The illustrated conduits 10, 30, 50, comprises a single, unitarypiece of material (excepting the reinforcing component) that has beenformed into a desired configuration. This construction may be preferableto minimize the risk of material separation or other adverse effects tothe structural integrity of the conduit. Nonetheless, the conduit of theinvention may comprise several pieces of material secured together.Similarly, the reinforcing component may comprise a structural memberintegrally formed with or coupled to the conduit, or a reinforcingmaterial added to or impregnated in the material forming the conduit.

[0074] An exemplary conduit formed of discrete pieces of material isdesignated by reference numeral 60 in FIG. 6 and includes a firstconduit portion 62 and a second conduit portion 64 which correspond,respectively, to the first and second conduit portions of the previousembodiments. As such, the first conduit portion 62 has at least oneinlet 66 while the second conduit portion 64 has at least one outlet 68.The conduit portions 62, 64 are joined at ajunction 70 by suitablemeans, e.g., adhesives, thermal bonding, mechanical attachment, etc. Thefirst conduit portion 62 has a free end 72 defining the inlet 66 and thesecond conduit portion 64 has two free ends 74 defining two outlets 68.The illustrated conduit 60 does not include a reinforcing componentcoupled to or formed with the body of the conduit; however, theabove-described reinforcing components may be used, or the conduit 60may be partially or completely coated (or otherwise treated) with alayer of reinforcing material that prevents collapsing or kinking of theconduit.

[0075] The first conduit portion 62 of this embodiment has an oppositeend 76 which is bifurcated into two flaps 78 each of which is secured tothe conduit portion 64 by any of the aforementioned means. The edges ofthe flaps 78 may be tapered or feathered (as shown) to make a smoothtransition with the exterior of the second conduit portion 64, therebyminimizing the amount of material to be introduced into the lumen of thetarget vessel. It also may be preferable to minimize the wall thicknessof the material used to further reduce the amount of material that mustbe accommodated when the second conduit portion is placed in the targetvessel lumen, without sacrificing preferential blood flowcharacteristics or the structural integrity of the conduit.

[0076]FIG. 7 shows a conduit 80 constructed according to anotherembodiment of the invention. The conduit 80 includes first and secondconduit portions 82, 84 secured together and having, respectively, aninlet 86 and a pair of outlets 88. The second conduit portion 84 has apair of free ends 90 that define the outlets 88. The free ends 90 of thesecond conduit portion 84 are provided with reinforcing components 92which engage and support the wall of the target vessel adjacent theoutlets 88.

[0077] Each reinforcing component 92 preferably has a beveled, slightlyenlarged end 94, e.g., as a barb, for easy introduction into the targetvessel lumen, although only one of the components 92 may be beveledand/or enlarged. Each component 92 also has a step 96 for receiving asuture (not shown) or other fastening means that may be used to enhanceattachment between the second conduit portion 84 and the target vessel.It will be appreciated that the specific construction of the reinforcingcomponents 92 and the conduit 80 may be different from that shown, e.g.,grooves, slots, resilient collars, roughened surfaces, etc.

[0078]FIGS. 8 and 8A illustrate a conduit 100 constructed according toanother embodiment of the invention. The conduit 100 is similar to theconduit 80 and includes first and second conduit portions 102, 104defining, respectively, an inlet 106 and a pair of outlets 108. Thefirst conduit portion 102 has an end secured to the second conduitportion 104 at ajunction 110 by any of the means described herein. Thesecond conduit portion 104 has a pair of ends 1 12 defining the outlets108, each end 112 being provided with a reinforcing component 114 toengage and support the wall of the target vessel adjacent the outlets108 (FIG. 8A).

[0079] The conduit 100 is constructed such that the reinforcingcomponents 114 do not come into direct contact with the luminal surfaceof the target vessel wall. As shown in FIG. 8A, the reinforcingcomponents 114 are disposed on the exterior of the second conduitportion 104; however, the ends 112 of the second conduit portion 104 areeverted at 116 so as to capture the reinforcing components 114. Thisensures that the material of the second conduit portion 104 (which hasbeneficial blood interface characteristics) contacts the blood flowingthrough the target vessel, rather than the reinforcing components 114.It will be understood that while the illustrated reinforcing components114 are sleeves that extend around the circumference of the ends 112 ofthe second conduit portion 104, they could have a differentconstruction, e.g., coil members, and they could extend around a portionof the ends of the conduit portion, e.g., by placing a plurality ofdiscrete members around some or all of the second conduit portion 104.

[0080] FIGS. 9-12 illustrate several conduits constructed according tofurther alternative embodiments of the invention. FIG. 9 shows a conduit120 including first and second conduit portions 122, 124 forcommunicating, respectively, with a source of blood and a target vessel.The conduit 120 has basically the same construction as the conduit 100described above, including reinforcing components 126 at the ends of thesecond conduit portion 124. The conduit 120 is configured for use inplacing a coronary vessel in fluid communication with a heart chambercontaining blood. To that end, the conduit 120 is provided with a device128 which is positioned in the myocardium (not shown in FIG. 9) anddirects blood to the second conduit portion 124 and the target vessel.

[0081] The device 128 is preferably capable of withstanding myocardialcontraction during systole so that the conduit 120 remains open duringuse. The construction and use of the device 128 may be in accordancewith the teachings of co-pending, commonly-owned application Ser. No.09/304,140, filed on May 3, 1999, and entitled “Methods and Devices forPlacing a Conduit in Fluid Communication with a Target Vessel,” theentire subject matter of which application is incorporated herein byreference. It will be recognized that the first conduit portion could besecured to tissue by other means, for example, suture, fasteners,clamps, clips, etc.

[0082]FIG. 10 shows a conduit 130 including first and second conduitportions 132, 134, which, as in the previous embodiment, respectivelycommunicate with a heart chamber containing blood and a coronary vessel.The conduit 130 includes reinforcing components 136 on the ends of thesecond conduit portion 134, as well as the device 128 described above inconnection with the previous embodiment. The conduit 130, rather thanbeing generally T-shaped, has a different configuration due to thelongitudinal axes (not shown) of the first and second conduit portions132, 134 being arranged in a nonperpendicular fashion.

[0083] Specifically, the first conduit portion 132 extends away from thesecond conduit portion 134 at an angle 0 which, in the illustratedembodiment, is approximately 45°. It may be desirable to angle the firstand second conduit portions with respect to each other to achievedifferent flow characteristics, the particular configuration shown inFIG. 10 being exemplary only. The angle θ is preferably within a rangeof from about 10° to about 90°, e.g., 15°, 30°, 45°, 60°, etc., and mostpreferably 45°.

[0084]FIG. 11 shows a conduit 140 constructed according to yet anotherembodiment of the invention, the conduit 140 including first and secondconduit portions 142, 144. As in the previous embodiment, the first andsecond conduit portions 142, 144 are respectively placed incommunication with a heart chamber containing blood and a coronaryvessel. Also as in the previous embodiment, the conduit 140 includesreinforcing components 146 on the ends of the second conduit portion144, and the device 128 for coupling the conduit to tissue. The conduit140, and in particular the first conduit portion 142, is constructedwith a preformed curvature 148 to aid in locating the second conduitportion 144 in a coronary vessel and the second conduit portion 142 inthe myocardium. The curvature may be imparted to the conduit 140 in anysuitable manner, for example, by forming the conduit on a curvedmandrel.

[0085]FIG. 12 shows a conduit 150 constructed according to still anotherembodiment of the invention. The conduit 150 includes first and secondconduit portions 152, 154, and a device 128 for coupling the conduit totissue. The second conduit portion 154 has one or more beveled ends 156(but not the reinforcing components included in the conduits 120, 130 or140). The conduit 150 instead has a reinforcing component 157 having acoiled construction that is the same as (or similar to) the reinforcingcomponent 26 described in connection with FIGS. 1-2. The first conduitportion 152 has a preformed curvature 158 to aid in locating the secondconduit portion 154 in a coronary vessel. The curvature 158, however, isless severe than the curvature 148 of the conduit 140. It will beappreciated that the conduits 140, 150 of FIGS. 11 and 12 are only twoexamples of the many possible conduit shapes, as various degrees ofcurvature may be imparted to the first conduit portion.

[0086] FIGS. 13A-13B show a conduit 160 constructed according to stillanother embodiment of the invention. The conduit 160 has first andsecond conduit portions 162, 164 for purposes explained above. Thesecond conduit portion 164 in this embodiment is movable betweencollapsed (FIG. 13A) and expanded (FIG. 13B) orientations to aid inintroducing the portion 164 into the target vessel. The second conduitportion 164 has a pair of free ends 166 provided with resilient elements168 that permit the ends 166 to move longitudinally toward and away fromthe first conduit portion 162 while remaining generally aligned with thelongitudinal axis of the portion 164. The illustrated elements 168 arecoil springs; however, alternative elements could be used, for example,self-expanding or balloon-expandable stents. The second conduit portion164 may be collapsed to the position shown in FIG. 13A for quick andeasy introduction into the target vessel lumen and, once disposedtherein, expanded to the position shown in FIG. 13B.

[0087] FIGS. 14A-14C show a conduit 170 which is constructed accordingto another embodiment of the invention and includes first and secondconduit portions 172, 174. As in the embodiment of FIGS. 13A-13B, thesecond conduit portion 174 is movable between collapsed (FIG. 14A) andexpanded (FIG. 14B) orientations to aid in introducing the conduitportion 174 into the target vessel. The second conduit portion 174 isconstructed so that it may be collapsed in a radial direction, forexample, by being folded as indicated at 176 in FIG. 14C, which reducesthe profile of the portion 174 for easier introduction into the targetvessel lumen. The second conduit portion may be self-expanding or it maybe expanded by force applied, for example, by a balloon. While theillustrated second conduit portion 174 is not provided with resilientelements as in the previous embodiment, they could be included to aid incollapsing and expanding the portion 174. The second conduit portion 174is placed in the target vessel and expanded to the position shown inFIG. 13B such that the ends 178 of the portion 174 engage the vesselwall.

[0088] It should be recognized that the embodiments of FIGS. 13A-13B and14A-14C are illustrative in that a conduit constructed according to theinvention may be collapsible in additional or alternative fashions. Forexample, with respect to the embodiment of FIGS. 13A-13B, the secondconduit portion 164 could be collapsed axially by folding or rollingeach leg toward the first conduit portion 162. Similarly, with respectto the embodiment of FIGS. 14A-14C, the second conduit portion 174 couldbe collapsed radially by folding or rolling the portion in a spiralfashion. Further, the second conduit portion could be collapsibleaxially or longitudinally, as shown in FIGS. 13A-13B, as well ascollapsible radially, as shown in FIGS. 14A-14B, by utilizing a materialthat expands both radially and longitudinally. For example, the materialdisclosed in U.S. Pat. No. 4,955,899 may be used, the disclosure ofwhich is incorporated herein by reference.

[0089] FIGS. 15-17 show conduits constructed according to otherembodiments of the invention. The conduit 180 of FIG. 15 has a firstconduit portion 182 and a reduced size second conduit portion 184. Thelength of the second conduit portion 184 is between one and two timesthe diameter of the first conduit portion 182. FIG. 16 shows a conduit186 including a first conduit portion 188 and a second conduit portion190, the first conduit portion 188 having a restricted section 192adjacent the conduit portion 190. FIG. 17 shows a conduit 194 that isgenerally L-shaped and includes first and second conduit portions 196,198. The first and second conduit portions 196, 198 meet at a junctionsuch that the portion 198 slightly flares away from the portion 196,thereby engaging and sealing against the edges of the incision in thetarget vessel wall (not shown) to prevent blood leaking out of thelumen.

[0090] FIGS. 18A-18B and 19A-19B shows conduits constructed according toother embodiments of the invention. The conduit 200 (FIGS. 18A and 18B)includes first and second conduit portions 202, 204, with a device 206coupled to the portion 204 for communicating with the heart chamber. Thefirst conduit portion 202 has an inlet 208 and includes multiple bends210 a, 210 b which serve to align the second conduit portion 204 withthe axis of the target vessel. The second conduit portion 204 includesone outlet 212, which gives the conduit an L-shaped configuration,received in the vessel to deliver blood from the chamber into the vessellumen.

[0091] The conduit 220 (FIGS. 19A and 19B) includes first and secondconduit portions 222, 224 and a device 206 for communicating with theheart chamber. The first conduit portion 222 has an inlet 226, while thesecond conduit portion 204 has a pair of outlets 228, giving the conduit220 a T-shaped configuration. The conduit 220 includes multiple bends230 a, 230 b which are similar to bends 210 a, 210 b (described above)and serve to align the second conduit portion 224, and in particular theoutlets 228, with respect to lumen of the target vessel. The bends 21Oa,210 b and 230 a, 230 b may be imparted to their respective conduit invarious manners. For example, a mandrel having a shape and sizecomplementary to that of the conduit may be dipped in a suitablebiocompatible material, e.g., silicone, and then heated or subjected toother conditions to cause the material to set and form the desiredconduit configuration. Two or more bends are preferably imparted to theconduit so as to lie in two transverse planes, for example,substantially perpendicular planes as in the embodiments of FIGS.18A-18B and 19A-19B. It should be recognized, though, that theparticular angular orientation used, as well as the overallconfiguration of the conduit, may be varied depending on the specificapplication and user preference.

[0092] The multiple bends in the embodiments of FIGS. 18A-18B and19A-19B allow the conduit communicating with the heart chamber to beplaced through the myocardium at a location that is spaced from thecoronary vessel. This is contrast to placing a conduit transmurallythrough the myocardium between the inner or posterior wall of the targetvessel and the heart chamber so that blood flows directly through theheart wall into the vessel lumen. This provides flexibility in that theportion of the conduit communicating with the heart chamber may beplaced through the myocardium at different locations while stillaccessing the target vessel in a desired manner with another portion ofthe conduit, a particularly useful feature in situations presentinglimited access to the heart or target vessels.

[0093] The conduits of the invention may be formed of any materialsuitable for use in a blood-contacting application, for example,synthetic vascular graft materials such as expandedpolytetrafluoroethylene (PTFE) and polyethylene terephthatlate (Dacron).Other suitable synthetic materials include polyurethanes, such asTecoflex, polycarbonate polyurethane—PCPU, such as Biospan (Corethane),and silicone, such as MED-4850, MED-6640, and MED-gumstock, allcommercially available from NuSil Technology of Carpinteria, Calif. Theconduit may also be formed of metal or a metallic alloy such astitanium, stainless steel, and nickel titanium. Finally, it should benoted that the conduit could comprise a tissue graft, for instance, asaphenous vein graft harvested from the patient, an allograft or axenograft. It will also be appreciated that the conduit may comprise anyof the aforementioned materials alone or in combination. Also, theconduits may be provided with means for detecting its position, e.g.,radiopaque markers, during or after placement of the conduit in thetarget vessel, thereby allowing the user to confirm the position of andblood flow through the conduit.

[0094] The reinforcing component of the invention is preferably formedof any biocompatible material that will provide the conduit with adesired amount of structural support. Examples of suitable materialsinclude Dacron, or polyethylene terephthatlate (PET), Nylon, titanium,stainless steel, nickel titanium, etc. The reinforcing component couldtake various forms, including the coiled structure shown in FIGS. 1 and2, a braided structure, a stent or stent-like structure, knitted fabric,woven mesh, and a tubular (or semi-tubular) element.

[0095] The conduit may also be constructed to minimize or preventkinking or collapsing without incorporating a reinforcing component, forexample, by coating or impregnating the conduit with a material thatprovides a desired amount of structural rigidity, such as silicone,polyurethane, PTFE, or another polymer, which would not adversely affectthe flexibility or structural integrity of the conduit. For example, acoating could be placed on the interior of the conduit to maintain theconduit-blood interface while providing a strain relief-type structureto minimize or prevent kinking. The coating could, however, also belocated on the exterior of the conduit (in addition to or instead of theexterior). The conduit may be provided with additional coatings selectedprovide particular qualities, for example, antithrombogenic,antimicrobial lubricious, etc., coatings.

[0096] The conduit of the invention is preferably relatively flexible sothat it may bend or flex during use, although it may be stiff orsubstantially rigid if desired. The degree of flexibility (or rigidity)imparted to the conduit may vary depending on the particular applicationand user preference. As an example, in a coronary application theconduit portion placed in the coronary vessel may comprise a materialhaving a Shore hardness in the range of from about 80A to about 55D,this range being preferable because it provides sufficient structuralintegrity while allowing some flexibility for easier deployment.

[0097] In addition to, or in lieu of, providing the conduit with astrain relief element to counteract collapse or kinking, the conduit (orportion of the conduit) may be specifically formed to prevent kinking,for instance, by imparting a preformed bend to one or more desired areasof the conduit, as exemplified by the conduits 140, 150 shown in FIGS.11-12. The conduit of the invention may be straight, tapered, curved,stepped, or otherwise configured over or all or a part of its length.Also, the conduit may be formed with a curved, malleable or bendableportion, or an articulated portion that may be controlled or steered byknown mechanisms used to steer catheters or guide wires.

[0098] Turning to FIGS. 20A-30E, exemplary embodiments of methods forplacing a conduit in fluid communication with a target vessel and asource of blood according to the invention will be described. Theseembodiments show a conduit being used to place a coronary vessel, suchas a coronary artery or vein, in fluid communication with a heartchamber, such as the left ventricle. It will be understood, however,that these particular applications are set forth for explanatorypurposes and are not intended to restrict or limit application of theinvention to other body structures.

[0099] In the illustrated and preferred embodiments, the conduit issecured to the target vessel by a substantially suture-free attachment;thus, the attachment is not a conventional hand-sewn anastomosis createdby suturing the members together. Although some suture may be used, theconduit is preferably coupled to the target vessel by means other than atypical, hand-sewn sutured connection. It will nonetheless beappreciated that the invention may be practiced using suture to secure(partially or completely) the conduit to the target vessel.

[0100]FIG. 20A is an anterior view of a heart H showing the leftventricle LV, right ventricle RV, right atrium RA, aorta A, pulmonarytrunk PT and pulmonary veins PV. The left coronary artery, including itsleft anterior descending branch LAD, is visible in this view, as is theright coronary artery RCA. Also shown is a diagonal branch D of the LAD.The coronary arteries run along the myocardium and deliver oxygenatedblood to the myocardial tissue. An occlusion or stenosis O partially (orcompletely) obstructs the lumen of the LAD, which results in inadequateor no blood flow to the myocardial tissue fed by the portion of the LADthat is downstream of the occlusion O. It will be appreciated that theocclusion O could be located in another coronary artery, or in adifferent location in the LAD, for example, proximal rather than distalto the diagonal branch D.

[0101]FIG. 20A shows a conduit 240 constructed according to theinvention positioned adjacent the heart H. The conduit 240 includesfirst and second conduit portions 242, 244 adapted to be placed incommunication with a heart chamber and a target vessel, respectively.The conduit 240 includes a device 128 for establishing communicationwith a heart chamber while securing the conduit in the desired position,as well as a reinforcing component for supporting the walls of theconduit.

[0102]FIG. 20B depicts the heart H shown in FIG. 20A after the secondportion of the conduit 240 has been deployed in the target vessel. Thedevice 128 is inserted into the tissue of the myocardium, either beforeor after deployment in the target vessel, so as to be in fluidcommunication with a heart chamber containing oxygenated blood (the leftventricle LV in the illustrated embodiment). The first conduit portion242 extends from the device 128 to the coronary vessel being treated(the LAD in the illustrated embodiment). The second conduit portion 244is disposed in the LAD at a location distal to the occlusion 0 so as tocontact and seal against the luminal surface of the vessel wall. As aresult, blood flows from the left ventricle LV into the conduit 240 andthe lumen of the LAD to perfuse myocardial tissue distal to theocclusion 0, which tissue had been deprived of oxygenated blood due tothe occlusion.

[0103]FIG. 20C is an enlarged view of a portion of the heart H shown inFIG. 20B. The device 128 is shown positioned in the myocardium M so asto communicate with the left ventricle LV (the reinforcing componentbeing omitted in this view). The device 128 is preferably sized so thatwhen positioned it extends completely through the myocardium M andprojects slightly into the left ventricle LV and slightly beyond theexterior of the myocardium. Alternatively, the device 128 couldterminate within the myocardium with a distal segment of the firstconduit portion 242 extending into the myocardium. As anotheralternative, the device 128 could be omitted and the first conduitportion 242 positioned in the myocardium so as to extend into the leftventricle, the portion 242 being constructed to withstand myocardialcontraction during systole without collapsing.

[0104] In any case, it may be desirable to first measure the thicknessof the myocardium, either approximately or precisely, at the area thatwill receive the device 128 (or the distal segment of the first conduitportion 242). The device 128 may then be placed with its ends properlypositioned with respect to the left ventricle and the exterior of themyocardium. Any suitable means for determining the thickness of themyocardium may be used prior to placing the conduit 240. For example, aninstrument having markings may be inserted through the myocardium togauge the myocardial thickness. The instrument, for example, a probe,may have a member on its distal end that is engaged with theendocardium, thereby allowing the user to read the markings disposedadjacent the exterior of the heart. Alternatively, an instrument havinga flashback lumen may be used so that entry into the heart chamber isindicated or verified by a blood flash, the instrument having markingsthat may be read to determine myocardial thickness or verify entry intothe source of blood (or the target vessel). Other means for determiningmyocardial thickness include transesophageal echocardiography (TEE),magnetic resonance imaging, CT scanning and electronic probes.

[0105] The second conduit portion 244 includes two outlets 246 and maybe placed into the lumen of the LAD through an incision I and, ifdesired, secured in place by suture S. It should be noted that if theocclusion 0 is not complete (or if blood from collateral vessels feedsinto the LAD proximal to the conduit 240), the outlet 246 that isproximal to the first conduit portion 242 (the outlet to the left inFIG. 20C) also acts as an inlet as blood enters this outlet and flowsdistally. During diastole, this blood may be drawn from the vessel intothe left ventricle due to the relatively low ventricular pressure, asdiscussed further below.

[0106] The second conduit portion 244 will typically be placed in thetarget vessel distal to the occlusion by a distance that permits easierintroduction into the lumen, as opposed to entering a diseased orstenosed section of the vessel. This results in a space located betweenthe occlusion 0 and the conduit outlet 246 that is disposed nearest theocclusion (the outlet to the left in FIG. 20C). Thus, if the conduitdoes not provide blood flow toward the occlusion 0, this space, and moreparticularly the myocardial tissue fed by this section of the LAD, maybecome ischemic, particularly if the occlusion totally blocks any nativeflow through the vessel from an upstream source.

[0107] Accordingly, the preferred embodiments of the invention utilizeconduits that are configured to deliver blood into the target vessel inmultiple directions to fully revascularize the myocardial tissueperfused by the vessel. As shown in FIG. 20C, blood flows into thesecond conduit portion 244 and exits the outlets 246 in more than onedirection, as indicated by the arrows. In the illustrated embodiment thedirections are along a common axis and opposite each other, but it willbe recognized that the embodiment of FIGS. 20A-20C is only one possibleconfiguration that will result in blood flowing into the target vesselin multiple directions. As such, the invention encompasses deliveringblood into the target vessel in multiple directions that are notopposite each other. For example, rather than being T-shaped, anL-shaped conduit such as conduit 294 shown in FIG. 17 may be used. Itshould be recognized that the invention encompasses conduits that arenot T or L-shaped but are still configured to achieve flow in more thanone direction within the target vessel.

[0108] The multiple outlets in the preferred conduit permit subsequentaccess to the conduit (i.e., post procedure) by delivering a guidewireor catheter percutaneously through the patient's vascular system. Forexample, the catheter may be delivered into the coronary vessel andmoved past the occlusion, if possible, and then used to guide a deviceto the conduit location, e.g., a plaque ablation or removal device.

[0109] In an application utilizing the left ventricle as the bloodsource, such as that depicted in FIGS. 20A-20C, the direction and volumeof the blood flow in the coronary vessel will vary during the systolicand diastolic phases of the heart cycle. More particularly, duringsystole the pressure in the left ventricle is at its maximum,approximately 120 mm Hg, which forces blood into the conduit 240. Theblood flows from the first conduit portion 242 into the second conduitportion 244 and passes through the outlets 246 into the LAD. The highpressure in the left ventricle drives the blood in multiple directionsto perfuse the myocardium both proximally and distally to the secondconduit portion 244.

[0110] During diastole, the pressure in the left ventricle is at itsminimum, approximately 5-10 mm Hg, while the pressure in the LAD isapproximately 80 mm Hg. This pressure differential results in bloodbeing drawn from the LAD into the left ventricle, which would seeminglycounteract the delivery of blood to the LAD during systole. It isbelieved, however, that this backflow of blood into the left ventricle(which may be characterized as “steal” in that blood is being taken fromthe coronary artery) does not prevent adequate perfusion of themyocardial tissue fed by the distal LAD. In the case of a partialproximal obstruction in the LAD, any blood flowing from the aorta thatis stolen into the left ventricle should not prevent adequaterevascularization insofar as the aorta may be considered an infinitesource. In the case of a complete obstruction in the LAD, any blood thatis stolen into the left ventricle will be taken from the distal LAD;however, testing of the inventive conduits has shown that the myocardialtissue is adequately perfused despite a complete proximal obstruction inthe LAD. Adequately perfused means that a threshold level of oxygenatedblood is being delivered to the myocardial tissue to allow the heart tofunction within acceptable limits.

[0111] The conduits of the invention could be provided with a checkvalve to prevent backflow of blood into the left ventricle. This design,though, is presently not as preferred as a non-valved conduit. Onesignificant benefit provided by a non-valved conduit is that blood flowthrough the conduit is essentially constant, although in differentdirections, which prevents hemostasis in the conduit. As such, not usinga valve and allowing backflow through the conduit prevents or reducesthe likelihood of thrombosis (clotting) in the conduit, which is aprimary concern with any device (like a valve) that is placed in a bloodflow path. Consequently, the washing effect provided by blood flowingthrough the conduit is believed to obviate thrombosis orthrombosis-related problems. This is in contrast to a valved conduitthat closes during diastole and thus results in blood remainingstationary in the conduit during a phase of the heart cycle.

[0112]FIGS. 21A and 21B show the conduits 200, 220 of FIGS. 18A-18B and19A-19B positioned in a coronary vessel CV with the device 206 in fluidcommunication with a heart chamber C containing blood. As shown, asignificant portion of the length of each conduit 200, 220 is disposedexternal to the myocardium M; the relative length of material that iswithin tissue (transmural) and external may be varied from that shown.FIGS. 22A and 22B show alternative conduit configurations whereinsubstantially all of the length of the conduit is disposed withintissue. FIG. 22A shows a conduit 232 with a portion 234 located in acoronary vessel, another portion of the conduit 232 including a device206 in communication with a heart chamber C. FIG. 22B shows a conduit236 having a target vessel portion 238 located in a coronary vessel,with another portion of the conduit 238 provided with a device 206 forcommunicating with the heart chamber C. Other conduit configurations maybe used as well; for example, the partial tubular conduits shown inFIGS. 4 and 5 may be used in a transmural application such as thoseshown in FIGS. 22A and 22B.

[0113] As noted above, the LAD is only one example of a coronary vesselthat may be treated according to the invention. FIG. 23 is a sectionalview of the heart H shown in FIG. 20C, taken along a generallyhorizontal line cutting through the myocardium and the LAD. The sectionline extends distal to the diagonal D, and the perspective of FIG. 23 islooking down toward the apex of the heart. This view shows the LAD andone of its diagonal branches D, the posterior descending branch, PDA, ofthe right coronary artery RCA, and the obtuse marginal branch, OM, ofthe circumflex artery.

[0114] A conduit 250 is shown deployed to communicate the left ventricleLV and the LAD, while a conduit 252 is shown deployed so as tocommunicate the left ventricle LV and the PDA. The conduits 250, 252 areconstructed as described above with respect to previous embodiments andinclude devices 128 that penetrate the epicardium EP, the endocardium ENand the myocardium M to communicate with the left ventricle LV. Thoseskilled in the art will appreciate that the diagonal D and the obtusemarginal OM represent additional coronary vessels that could be coupledto conduits placed in communication with the left ventricle LV. As such,it will be recognized that the target vessels shown in FIG. 23 areexemplary only.

[0115] The conduit of the invention may be introduced into the lumen ofthe target vessel via any suitable means. One preferred method is shownin FIGS. 24A-24D and comprises surgically forming an incision I in thewall W of a target vessel TV for receiving a conduit 260 including firstand second conduit portions 262, 264. The conduit 260 is similar to theconduit 30 of FIGS. 4-4A, except only the second conduit portion 264 isprovided with a reinforcing component. A distal end of the secondconduit portion 264 is inserted through the incision (FIG. 24A) and intothe vessel lumen. In this embodiment, the distal end of the secondconduit portion 264 is moved distally a sufficient distance to center orsubstantially center the conduit 260 in the vessel (FIG. 24B). Theproximal end of the second conduit portion 264 is then pushed into thevessel lumen (24C), which results in both legs of the second conduitportion 264 being in the lumen and away from the ends of the incision.This affixes the conduit 260 to the target vessel TV and preferablyprovides a fluid-tight seal.

[0116] It will be noted that the conduit 260 is deployed to its finalposition without substantially moving the second conduit portion 264within the target vessel lumen. That is, the conduit is not movedrelative to the vessel wall by an amount that risks damaging the intimalsurface of the vessel wall. Alternatively, the conduit may be deployedby sliding the distal end of the second conduit portion distally,placing the proximal end in the vessel lumen, and sliding the conduitproximally to anchor it to the vessel (in a manner somewhat similar tothat used by surgeons to place a perfusion bridge in a coronary arteryduring cardiac surgery).

[0117] The second conduit portion 264 will remain in location in thetarget vessel due to the anchoring provided by the proximal and distallegs of the second conduit portion 264. The attachment between theconduit and the target vessel should provide a hemostatic seal;therefore, if necessary, additional means for securing the conduit tothe vessel may be used, for example, suture (as shown in FIG. 24D),fasteners, clamps, clips, cuffs, gasket-like structures and fibrin orcollagen-based adhesives and sealants.

[0118] FIGS. 25A-25C illustrate an exemplary method for deploying acollapsible conduit 160 which has been described above with respect toFIGS. 13A-13B. Briefly, the conduit 160 includes first and secondconduit portions 162, 164, the latter defining free ends 166 providedwith a reinforcing component 168. The reinforcing component 168 allowsthe second conduit portion 164 to collapse along (or substantiallyalong) the longitudinal axis of the portion 164, which preferablygenerally coincides with the longitudinal axis of the target vessel.

[0119]FIGS. 25A schematically shows a retaining instrument 266 forholding the second conduit portion 164 in its collapsed orientation. Theretaining instrument 266 is a forceps-type device with a pair of arms268 for holding the conduit. The arms 268 have jaws 270 that engage thefree ends 166 of the second conduit portion 164 and retain thereinforcing component 168 collapsed while placed through an incision Iformed in the wall W of a target vessel TV. FIG. 25B shows the arms 268and the second conduit portion 164 disposed in the lumen of the targetvessel while still collapsed. The arms 268 are removed, as shown in FIG.25C, which allows the reinforcing component 168 and the second conduitportion 164 to assume their expanded orientation in engagement with thewall of the target vessel, thereby securing the conduit 160 to thetarget vessel. Other means may of course be used to hold the conduitcollapsed, for example, an instrument that engages the interior of theconduit to restrain the second conduit portion 164.

[0120] FIGS. 26A-26C illustrate another exemplary method for deploying acollapsible conduit 170 in a target vessel, the conduit 170 having beendescribed above with respect to FIGS. 14A-14B. The conduit 170 has firstand second conduit portions 172, 174, but does not include a reinforcingcomponent. The second conduit portion 174 is collapsible about (orsubstantially about) the longitudinal axis of the portion 174, i.e., itis radially collapsible. In FIG. 26A, a retaining instrument 272 holdsthe second conduit portion 174 in its collapsed orientation. Theretaining instrument 272 includes two elements 274 that engage thecollapsed ends 178 of the second conduit portion 174. The elements 274are cup-shaped to receive the folded ends 178 of the conduit, and areconnected to and manipulated by a pair of shafts 276.

[0121]FIG. 26A shows the second conduit portion 174 held collapsed bythe retaining instrument 272 while being introduced through an incisionI in the wall W of a target vessel TV. FIG. 26B shows the second conduitportion 174 disposed in the vessel lumen with, as indicated by thearrows, the shafts 276 being moved toward the vessel to separate theelements 274 from the conduit ends 178. As shown, this allows the secondconduit portion 174 to assume its expanded orientation (which is largerin cross-section than the elements 274). Once the second conduit portion174 has been expanded, the shafts 276 are moved as shown to remove theelements 274 through the first conduit portion 172. The incision I maythen be sutured and sealed, as explained above.

[0122] The collapsible conduit retaining instruments 266 (FIGS. 25A-25D)and 272 (FIGS. 26A-26C) are depicted somewhat schematically as they areonly intended to represent some of the various devices that may be usedto deploy a collapsible conduit according to the invention. For example,a delivery device may include a sheath(s) that retains a portion of theconduit collapsed. The delivery device could incorporate other removablesecuring means, such as suture, to retain the conduit in its collapsedstate. Accordingly, it will be recognized that this aspect of theinvention may be practiced independently of any particular type ofintroducing instrument.

[0123] Another embodiment of a device and method for deploying a conduitin a target vessel according to the invention will be described withrespect to FIGS. 27-29A and 30A-30E. FIG. 27 shows a delivery deviceindicated by the reference numeral 280 for use in deploying a conduit ina target vessel while maintaining some level of perfusion duringdeployment. The device 280 is used to introduce a conduit into the lumenof the target vessel, the conduit being coupled to a source of bloodthat will be delivered to the vessel upon attachment of the conduit tothe vessel. As a result, this embodiment of the invention minimizesischemic time during deployment by perfusing the target vessel distallyof the attachment site between the conduit and the vessel.

[0124] The delivery device 280 includes an inner component preferably inthe form of an obturator 282 and an outer component preferably in theform of a sheath 284 (FIG. 28). The obturator 282 is movable withrespect to the sheath 284. The obturator 282 has a distal end 286 thatslightly projects beyond the distal end of the sheath 284, as shown inFIG. 27. The sheath has a hub 288 with threads 290 for engaging thethreads 292 carried by a cap 294 mounted to the obturator 282. Thedistal end portions of the obturator 282 and the sheath 284 arepreferably tapered and have complementary shapes that provide a smoothtransition for atraumatic insertion into the target vessel. The threads290, 292 provide a quick turn luer-type connection, althoughnon-threaded attachment mechanisms may be used. The sheath 284 has oneor more openings 296 passing into the sheath interior, these openingsbeing blocked when the obturator 282 is within the sheath 284 (FIG.29A). FIG. 28 also shows a cap 298 that may be attached to the sheathhub 288 to seal the hub after removing the obturator 282.

[0125]FIG. 29 shows the delivery device 280 of FIGS. 27-28 supporting aconduit 300 constructed according to the invention. The conduit 300includes first and second conduit portions 302, 304 and a device 128configured to be placed in communication with a heart chamber containingblood, as described above. The second conduit portion 304 is mounted onthe sheath 284 with the proximal end (to the right in FIG. 29) of theconduit portion 304 abutting the sheath hub 288, which holds the conduit300 in position during delivery. In FIG. 29A blood flowing from a source(not shown) to the conduit 310 is indicated by arrows. As can be seen,blood flowing through the first conduit portion 302 is prevented fromentering the lumen of the sheath 284 because the sheath openings 296 areblocked by the obturator 282. As such, the first conduit portion 302 maybe coupled to the blood source and the second conduit portion 304mounted on the device 280 and manipulated without leakage of blood.

[0126] FIGS. 30A-30E depict an illustrative method of using the deliverydevice 280 to introduce and deploy a conduit in a target vesselaccording to the invention. FIG. 30A shows a conduit 310 including firstand second conduit portions 312, 314 respectively adapted to becommunicated with a source of blood and a target vessel. The source ofblood is indicated schematically as it will be appreciated any suitablesource may be used, e.g., a heart chamber, the aorta, a coronary arteryor vein, a peripheral artery or vein, etc. Similarly, the target vesselTV may be a coronary artery or vein, a peripheral artery or vein, or anyother luminal body structure.

[0127]FIG. 30A shows the distal end portion of the device 280 insertedthrough an incision I in a target vessel wall W so as to place thedistal end 316 of the second conduit portion 312 within the vessellumen. The soft atraumatic end 286 of the obturator minimizes any tissuedamage during introduction. In FIG. 30A, the obturator 282 blocks thesheath openings 296 such that blood flowing from the source through thefirst conduit portion 310 is prevented from entering the sheath 284, asindicated by the arrows. FIG. 30B shows the next step, removing theobturator from the sheath 284 by moving the obturator cap 294proximally. The distal end 286 of the obturator must clear one or moreof the sheath openings 296 in order for blood from the source to flowthrough the first conduit portion 310 and into the sheath 284. At theposition depicted in FIG. 30B, the obturator 282 still blocks the sheathopenings 296.

[0128]FIG. 30C shows the delivery device 290 after the obturator 282 hasbeen removed. As indicated by the arrows, blood from the source is nowfree to enter the sheath lumen via openings 296 and flow distally intothe target vessel as it passes out the end of the sheath 284. As aresult, despite the fact that minimal steps have been performed and theconduit 310 has not been fully deployed in or secured to the targetvessel, the delivery device 290 enables perfusion of the distalvasculature. Hence, the remaining delivery steps may be carried out withless risk of the tissue perfused by the target vessel becoming ischemicduring the procedure, a significant benefit in a coronary bypassprocedure.

[0129]FIG. 30C also shows the cap 298 secured to the sheath hub 288 toseal the sheath lumen and prevent blood from exiting the proximal end ofthe sheath. The cap 298 may have a mechanism that seals aroundinstruments introduced into the sheath 284 and/or secures the instrumentto the sheath 284 and the cap 298. Any suitable mechanism may be used,e.g., a Tuohy-Borst compression adapter or a self-sealing septum.

[0130]FIG. 30D shows the delivery device 290 being moved proximally toseparate the sheath 284 from the second conduit portion 314, duringwhich blood from the source continues to flow distally and perfuse thedistal vasculature. Upon completely removing the sheath 284 from thesecond conduit portion 312 (or as the sheath is being removed), theproximal end 316 of the conduit portion 312 is moved into the targetvessel lumen, as shown in FIG. 30E. This placement of the conduit 310results in blood from the source being delivered in multiple directionswhich, in FIG. 30E, are proximal and distal along the longitudinal axisof the vessel, as indicated by the arrows.

[0131] A variation of the delivery device shown in FIGS. 30A-30Eutilizes a hollow obturator with one or more openings passing into alumen. The sheath is omitted in this embodiment, and blood from thesource flows through the second conduit portion, through the opening(s),and into the target vessel. The opening may be a slot extending along aportion of the length of the hollow obturator so that rotating theobturator within the first conduit portion moves the slot into or out ofalignment with the second conduit portion. In this manner, the devicecan be controlled, preferably from a proximal location, by rotating (orotherwise manipulating) the shaft to selectively allow or block flowinto the hollow obturator.

[0132] The conduit of the invention is preferably sized and configuredto form a blood flow path that is equal or substantially equal to theblood flow path defined by the native vessel. In other words, theconduit preferably defines an inner diameter that equals orsubstantially equals (e.g., 90% of) the inner diameter of the nativevessel. As a result, when placed in the target vessel the conduit allowsa sufficient volume of blood flow. If the target vessel is a coronaryartery, this ensures that blood will flow to the distal vasculature andperfuse the myocardial tissue.

[0133] The overall size and relative dimensions of the conduit will varydepending on the application. For sake of example, with reference toFIGS. 1, 1B and 2, it can be seen that the length and diameter of thefirst conduit portion 12 are greater than the length L2 and diameter D2of the second conduit portion 14. As an example, the length L1 of thefirst conduit portion 12 may be within a range of from about 20 mm to 80mm, and more preferably a range of from about 30 mm to 50 mm, while thelength L2 of the second conduit portion 14 is preferably within therange of 3 mm to 20 mm, and more preferably within the range of 5 mm to15 mm. When deployed in the application shown in FIG. 21, for example,approximately 25 mm of conduit (including the portion extending into thehear chamber) is placed in the myocardium, approximately 15 or 16 mm ofconduit is placed in the coronary vessel, and approximately 15 mmextends externally to the myocardium.

[0134] Similarly, the diameter D1 (and in particular the inner diameter)of the first conduit portion 12 may vary but is preferably within therange of from about 2 mm to 10 mm, and more preferably within the rangeof from 3 mm to 4 mm. The diameter D2 of the second conduit portion 14will be dictated primarily by the size of the lumen of the target vesselbeing treated. As an example, for use in coronary vessels, the diameterD2 (and in particular the inner diameter) of the second conduit portion14 is preferably within the range of 1 mm to 4 mm. It will berecognized, however, that these ranges are exemplary as the inventionencompasses conduits the dimensions of which fall outside such ranges byan amount that will not preclude their use in a desired application(cardiovascular or other).

[0135] The conduit of the invention also may be characterized by therelative dimensions of the respective conduit portions. For example,with reference to FIG. 2, if the length L2 of the second conduit portion14 is greater than D1, then some of the second conduit portion disposedin the target vessel lumen will extend beyond the ends of the incision(not shown in FIGS. 1-2). In an application involving a coronary arteryas the target vessel, the ratio of the diameter D1 (and in particularthe outer diameter) of the first conduit portion 12 to the length L2 ofthe second conduit portion 14 (D1/L2) is preferably within a range offrom about 1:1 to about 1:10, and more preferably within the range offrom about 1:2 to about 1:4.

[0136] The conduit of the invention may be manufactured by variousprocesses. It is currently preferred to mold the conduit of (orfabricate the conduit from) a material having desired blood interfacequalities as well as a desired combination of flexibility and columnstrength. Manufacturing processes and materials for forming the conduitsdisclosed herein are disclosed in co-pending, commonly owned applicationSer. No.______, filed on Sep. 10, 1999 (Attorney Docket No. 011) andentitled “Methods and Devices for Manufacturing a Conduit for Use inPlacing a Target Vessel in Fluid Communication With a Source of Blood,”the entire subject matter of which application is incorporated herein byreference.

[0137] The type of procedure (e.g., open chest, minimally invasive,percutaneous, etc.) that is used to deploy the conduit of the inventionmay vary depending on the vessels being treated and user preference. Asan example, a minimally invasive procedure may be used to deploy theconduit on a beating heart using various devices and methods forstabilizing all or a portion of the heart. Also, the conduits may becoupled to the target vessel other than as specifically shown herein.While several collapsible conduits are illustrated along with exemplarymethods for deploying them in a target vessel, it will be appreciatedthat the invention encompasses securing non-collapsible conduits to thevessel. For instance, the second conduit portion may be anon-collapsible, tubular member that is placed in the target vessellumen after first dilating the vessel wall, and then is retained byallowing the vessel wall to move back and snugly engage the exterior ofthe second conduit portion.

[0138] Moreover, the conduit may be used with a component that securesand preferably seals the conduit to the wall of the target vessel. Forexample, the component could comprise a sleeve or cuff member thatpartially or completely surrounds the conduit adjacent the target vesselwall. The vessel wall is effectively sandwiched between the componentand the intraluminal portion of the conduit, i.e., the conduit portionlocated in the vessel lumen (the second conduit portion in the aboveembodiments). The component exerts sufficient force toward theintraluminal portion of the conduit to secure the assembly to the targetvessel while providing adequate hemostasis at the attachment site. Thecomponent could be separate from or integral with the conduit, and couldbe constructed according to the teachings of co-pending, commonly ownedapplication Ser. No.______, filed on Sep. 10, 1999 (Attorney Docket No.012) and entitled “Anastomotic Methods and Devices for Placing a TargetVessel in Fluid Communication With a Source of Blood,” the entiresubject matter of which application is incorporated herein by reference.

[0139] It should also be noted that the conduits of the invention may beintroduced into a target vessel in various ways. For example, in theillustrated embodiment, the second conduit portion is inserted through asurgical incision in the vessel wall. An alternative arrangementincludes a delivery device on which the conduit is mounted, the devicehaving a permanent or detachable incising element with a sharpened tipfor penetrating the wall of the target vessel in conjunction withintroducing the conduit. Another arrangement uses a sheath thatrestrains a collapsible conduit and is removed to deploy the conduit.

[0140] Additionally, the conduits of the invention are preferably,though not necessarily, placed with the portion in the myocardium spacedfrom the portion in the coronary vessel. That is, the channel passingthrough the myocardium is not beneath or immediately adjacent thevessel. Nonetheless, as shown above the conduit may be positionedtransmurally in myocardial tissue directly or substantially beneath oradjacent the vessel. One benefit of the former method is that theconduit (or delivery device supporting the conduit) is introducedthrough the outer or anterior vessel wall to engage the lumen; it is notpassed through the inner or posterior vessel wall, which tends to bemore diseased than the outer wall.

[0141] It may be desirable to utilize a conduit delivery device having aportion surrounding the conduit to protect the conduit material prior toand during deployment. The device may have a bore that, in addition toreceiving the aforementioned optional incising element so that may beextended and retracted, is configured to act as a flashback lumen andindicate when the device has entered a lumen containing blood, forexample, a coronary artery or heart chamber. Of course, additionalmembers, for example, a guide wire or guide catheter, may be used todeliver the conduit.

[0142] The conduits of the invention may be provided with a valve orother means for controlling or regulating blood flow. Suitable valves,as well as means for measuring myocardial thickness or verifying entryinto the heart chamber, are disclosed in application Ser. No.09/023,492, filed on Feb. 13, 1998, and entitled “Methods and DevicesProviding Transmyocardial Blood Flow to the Arterial Vascular System ofthe Heart,” the entire subject matter of which has been incorporatedherein by reference. Likewise, the conduits may be provided with areservoir for retaining and discharging blood in a desired manner.

[0143] The conduits and delivery devices of the invention may be sizedand configured differently from that specifically illustrated in theFigures. For instance, the cross-section of one or more portions of theconduit may be noncircular, e.g., elliptical to better match the profileof the target vessel. As a further example, the delivery device may berelatively short with the shaft assembly substantially rigid for use inan open-chest procedure. Alternatively, the device may be configured foruse in either a minimally invasive or endosvascular procedure, whereinthe actuators for controlling the device components are located adjacentthe proximal end of the device to allow remote deployment of theconduit, for example, as disclosed in the aforementioned, co-pending,commonly-owned application Ser. No. 09/304,140.

[0144] It will be appreciated that the features of the various preferredembodiments of the invention may be used together or separately, whilethe illustrated methods and devices may be modified or combined in wholeor in part. As an example, more than one conduit may be coupled to amanifold that is placed in communication with one source of blood so asto deliver blood to multiple target vessels. The conduits and devices ofthe invention may include removable or detachable components, could beformed as disposable instruments, reusable instruments capable of beingsterilized, or comprise a combination of disposable and reusablecomponents.

[0145] Further, it will be understood that the embodiments may be usedin various types of procedures, for example, an open surgical procedureincluding a median stemotomy, a minimally invasive procedure utilizingone or more relatively small access openings or ports, or anendovascular procedure using peripheral access sites. Also, endoscopesor thoracoscopes may be used for visualization if the procedure isperformed through very small ports. The different embodiments may beused in beating heart procedures, stopped-heart procedures utilizingcardiopulmonary bypass (CPB), or procedures during which the heart isintermittently stopped and started.

[0146] It will be recognized that the invention is not limited to theillustrated applications. For example, the inventive conduits may beused in a CABG procedure by being coupled to an autologous conduit,e.g., a saphenous vein graft (or a nonautologous vessel such as axenograft, etc.). Further, the conduit could be coupled to a nativeartery, such as one of the internal mammary arteries, and then securedto the target vessel. Further still, the conduit may be coupled to anexisting CABG graft that has partially or completely occluded over timeby plugging the second conduit portion into the wall of the graft tocommunicate with the graft lumen distal to the occlusion.

[0147] It will be recognized that the invention may be used tomanufacture conduits the use of which is not limited to cardiovascularapplications such as those illustrated and discussed above. For example,the invention may be used to produce conduits used to carry out manydifferent bypass procedures, including, without limitation,femoral-femoral, femoral-popliteal, femoral-tibial, illo-femoral,axillary-femoral, subclavian-femoral, aortic-bifemoral, aorto-iliac,aorto-profunda femoris and extra-anatomic. The conduit may be used toestablish fluid communication with many different vessels, including,without limitation, the renal arteries, mesenteric vessel, inferiormesenteric artery, eroneal trunk, peroneal and tibial arteries. Stillother applications for the invention include arteriovenous shunts. Theconduit may have one, both or more ends configured to engage a targetvessel for receiving blood from or delivering blood to another vessel.

[0148] The preferred embodiments of the invention are described above indetail for the purpose of setting forth a complete disclosure and forsake of explanation and clarity. It will be readily understood that thescope of the invention defined by the appended claims will encompassnumerous changes and modifications.

What is claimed is:
 1. A method for delivering blood from a heartchamber containing blood to a target vessel of a patient's vascularsystem, the method comprising steps of: (a) placing a conduit having alumen in fluid communication with a heart chamber containing blood; (b)placing the conduit in fluid communication with the lumen of a targetvessel and securing the conduit to the target vessel; (c) deliveringblood from the heart chamber into the conduit during at least one phaseof the heart cycle; and (d) permitting the blood to flow from theconduit into the lumen of the target vessel in more than one direction.2. The method of claim 1, wherein a portion of the conduit extendingbetween the heart chamber and the target vessel is disposed on anexterior of the patient's heart.
 3. The method of claim 1, wherein theconduit is generally T-shaped and includes a first portion having onefree end and a second portion having two free ends, and step (a) isperformed by placing the first conduit portion through the myocardiumand at least partially within the heart chamber while step (b) isperformed by placing the second conduit portion at least partiallywithin the lumen of the target vessel.
 4. The method of claim 3, whereinthe first conduit portion is formed of a material having sufficientrigidity to avoid collapsing during myocardial contraction when placedaccording to step (a).
 5. The method of claim 4, wherein step (a) isperformed prior to step (b), and step (b) is performed by securing thesecond conduit portion to the target vessel via a substantiallysuture-free attachment.
 6. The method of claim 4, wherein the secondconduit portion is passed through a wall of the target vessel and placedat least partially within the lumen of the target vessel withoutcollapsing the second leg of the conduit, and blood flows within thelumen of the target vessel in two opposite directions.
 7. The method ofclaim 4, wherein the target vessel has a lumen that is at leastpartially obstructed by an occlusion, and the plurality of directionsinclude toward and away from the occlusion.
 8. A method for deliveringblood from a heart chamber containing blood to a target vessel of apatient's vascular system, the method comprising steps of: (a) placing aconduit having a lumen in fluid communication with a heart chambercontaining blood; (b) placing the conduit in fluid communication withthe lumen of a target vessel and securing the conduit to the targetvessel; (c) delivering blood from the heart chamber into the conduitduring at least one phase of the heart cycle; and (d) permitting bloodto flow out of the conduit unrestricted in more than one direction inthe lumen of the target vessel.
 9. The method of claim 8, wherein theconduit is disposed along the exterior of the heart.
 10. The method ofclaim 8, wherein the heart chamber contains oxygenated blood and thetarget vessel is a coronary artery.
 11. The method of claim 10, whereinthe heart chamber is the left ventricle, and blood flows from the heartchamber into the conduit and into the target vessel during both phasesof the heart cycle.
 12. A method for placing a target vessel of apatient's coronary vascular system in fluid communication with a heartchamber containing blood, the method comprising steps of: (a) providinga conduit including first and second portions that are disposedtransverse to each other and have lumens in fluid communication, thefirst conduit portion including at least one inlet and the secondconduit portion including at least one outlet; (b) placing the inlet ofthe first conduit portion in fluid communication with a heart chambercontaining blood to allow blood to enter the lumen of the first conduitportion; (c) positioning the outlet of the second conduit portion influid communication with the lumen of a target vessel at a selectedlocation in the target vessel to allow blood to flow into the lumen ofthe target vessel from the second conduit portion; and (d) securing thesecond conduit portion to the target vessel at the selected locationwhile substantially not moving the second conduit portion along alongitudinal axis of the target vessel.
 13. The method of claim 12,wherein the conduit is disposed along an exterior of the patient'sheart.
 14. The method of claim 12, wherein the second conduit portion ofthe conduit is secured to the target vessel via a substantiallysuture-free, end-to-side attachment.
 15. A method for deploying aconduit to deliver blood from a heart chamber to a target vessel of apatient's coronary vascular system, the method comprising steps of: (a)providing a conduit including first and second portions each of whichhas a lumen, wherein the first and second conduit portions are disposedtransverse to each other with the lumens in fluid communication and thesecond conduit portion is at least partially collapsible; (b) placingthe lumen of the first conduit portion in fluid communication with aheart chamber containing blood; (c) at least partially collapsing thesecond conduit portion and positioning the second conduit portion atleast partially within the lumen of a target vessel at a selectedlocation in the target vessel; and (d) expanding the second conduitportion within the lumen of the target vessel at the selected locationto secure the second conduit portion to the target vessel in fluidcommunication therewith.
 16. The method of claim 15, wherein the targetvessel is at least partially obstructed by an occlusion and the conduitis disposed along the exterior of the heart adjacent the myocardium, andthe second conduit portion has multiple outlets that direct blood towardand away from the occlusion.
 17. The method of claim 15, wherein step(c) is performed by making an incision in a wall of the target vesseland inserting the collapsed second conduit portion into the lumen of thetarget vessel, and step (d) is performed by removing a restrainingelement that holds the second conduit portion in a collapsed state. 18.A method for delivering blood from a heart chamber containing blood to atarget vessel of a patient's vascular system by placing conduit in themyocardium, the method comprising steps of: (a) determining a thicknessof the patient's myocardium adjacent a heart chamber containing blood;(b) placing a conduit having a lumen in the myocardium with the lumen ofthe conduit in fluid communication with the heart chamber containingblood; (c) placing the conduit in fluid communication with the lumen ofa target vessel and securing the conduit to the target vessel; and (d)delivering blood from the heart chamber into the conduit and allowingblood to exit the conduit and enter the target vessel in more than onedirection.
 19. A device for placing a target vessel of a patient'svascular system in fluid communication with a heart chamber containingblood, the device comprising: a conduit including first and secondportions, wherein the first and second conduit portions each have anaxis and a lumen through which blood may flow, the axes of the first andsecond conduit portions being transverse to each other; wherein thefirst conduit portion is configured to be placed in fluid communicationwith a heart chamber containing blood and includes at least one inletconfigured to be at least partially positioned in myocardial tissuewithout collapsing during myocardial contraction; wherein the secondconduit portion is configured to be at least partially positioned withinthe target vessel and includes at least one outlet adapted to deliverblood to the lumen of the target vessel; and wherein the inlet of thefirst conduit portion is more rigid than the outlet of the secondconduit portion.
 20. The device of claim 19, wherein the first conduitportion is at least partially formed of a rigid, non-compliant material,and the second conduit portion is at least partially formed of acompliant material.
 21. The device of claim 20, wherein the firstconduit portion comprises a rigid, metallic member and the secondconduit portion comprises a graft vessel.
 22. The device of claim 21,wherein the graft vessel is joined to the metallic member and comprisesa synthetic vascular graft material.
 23. The device of claim 19, furthercomprising a reinforcing member that extends at least partially alongthe conduit and provides at least the second conduit portion and theoutlet with a desired amount of rigidity.
 24. The device of claim 23,wherein the reinforcing member comprises at least one wire wrappedaround the first and second conduit portions.
 25. The device of claim24, wherein the wire is helically wrapped and has a smaller pitch lengthon the second conduit portion than the first conduit portion.
 26. Thedevice of claim 23, wherein the reinforcing member comprises at leastone sleeve coupled to the second conduit portion.
 27. The device ofclaim 26, wherein the sleeve is formed of a rigid material selected fromthe group consisting of PEEK, polyurethane, polyethylene, polypropylene,stainless steel, titanium, tantalum and a nickel-titanium alloy, and thesleeve is located adjacent the outlet.
 28. The device of claim 19,wherein the axes of the first and second conduit portions are generallyperpendicular such that the conduit is substantially T-shaped, and thefirst conduit portion corresponds to a first leg of the T having onefree end while the second conduit portion corresponds to a second leg ofthe T having two free ends.
 29. The device of claim 28, wherein thesecond conduit portion is configured such that the outlet may bedisposed and secured within the lumen of the target vessel withoutcontacting the entire circumference of the inner vessel wall.
 30. Thedevice of claim 29, wherein the second conduit portion is generallysemicircular in cross-section so as to leave the inner wall of thetarget vessel substantially uncovered.
 31. The device of claim 28,wherein at least one of the two free ends of the second conduit portionis expandable in at least one of an axial direction and a radialdirection.
 32. The device of claim 28, wherein at least one of the twofree ends has a beveled tip for introduction into the target vessel. 33.The device of claim 19, wherein the first and second conduit portionsmeet at a junction that is less rigid than the first or second conduitportion.
 34. A device for placing a target vessel of a patient'svascular system in fluid communication with a heart chamber containingblood, the device comprising: a conduit having first and second portionseach having a lumen, wherein the first and second conduit portions aredisposed transverse to each other with the lumens in fluidcommunication; wherein the first conduit portion has a longitudinal axisand is sized and configured to be placed in fluid communication with aheart chamber containing blood; wherein the second conduit portion has alongitudinal axis and is sized and configured to be placed at leastpartially within a target vessel in a patient's vascular system todeliver blood to the target vessel, the second conduit portion includingfirst and second ends adapted to be positioned in the target vessel; andwherein the longitudinal axis of the first conduit portion crosses thelongitudinal axis of the second conduit portion at a location that isspaced different distances from the first and second ends of the secondconduit portion.
 35. The method of claim 34, wherein the second conduitportion is provided with a selected amount of rigidity so as to beself-supporting yet compliant when in an expanded orientation, whilebeing at least partially deformable to a collapsed orientation forintroduction into the lumen of the target vessel.
 36. The device ofclaim 35, wherein the first and second conduit portions meet at ajunction, the first conduit portion being more rigid than the secondconduit portion, and the second portion of the conduit being more rigidthan the junction.
 37. The device of claim 34, wherein the first conduitportion comprises a rigid member configured to be positioned inmyocardial tissue, and the second conduit portion comprises a bifurcatedgraft vessel coupled to the rigid member.
 38. The device of claim 37,wherein the graft vessel comprises synthetic vascular graft materialselected from the group consisting of expanded polytetrafluoroethylene,polyethylene terephthalate, polyurethane and silicone.
 39. The device ofclaim 34, wherein the second conduit portion includes a reinforcingmember disposed adjacent one of the first and second free ends.
 40. Thedevice of claim 34, wherein the second conduit portion has first andsecond blood outlets.
 41. The device of claim 40, wherein thelongitudinal axis of the first conduit portion crosses the longitudinalaxis of the second conduit portion at a location that is spaceddifferent distances from the first and second blood outlets of thesecond conduit portion.
 42. The device of claim 34, wherein the conduitis generally T-shaped and the first conduit portion corresponds to oneleg of the T having one end while the second conduit portion correspondsto another leg of the T having two ends, and wherein the two ends of theother leg of the T define the first and second blood outlets and arespaced different distances from the one leg of the T.
 43. A device forplacing a target vessel of a patient's vascular system in fluidcommunication with a heart chamber containing blood by forming a bloodflow path between the target vessel and the heart chamber, the devicecomprising: a conduit having first and second portions each of which hasan axis, the axes of the first and second conduit portions beingtransverse to each other; wherein the first conduit portion has a freeend and is configured to be placed in fluid communication with a heartchamber containing blood, and the second conduit portion has two freeends that are sized and configured to be positioned at least partiallywithin the lumen of a target vessel in the patient's vascular system;and wherein the conduit is formed at least in part of a molded thermosetmaterial having a predetermined amount of flexibility to permit thesecond portion of the conduit to be flexed for placement within thelumen of a target vessel.
 44. The device of claim 43, wherein the firstconduit includes a member configured to be placed in myocardial tissuewithout collapsing during myocardial contraction.
 45. The device ofclaim 44, wherein the conduit is generally T-shaped and the firstconduit portion corresponds to one leg of the T having one free endwhile the second conduit portion corresponds to another leg of the Thaving two free ends, and wherein the two free ends of the other leg ofthe T define first and second outlets adapted to be placed in fluidcommunication with the lumen of the target vessel.
 46. The device ofclaim 45, wherein the second conduit portion conduit is configured suchthat the outlets may be disposed and secured within the lumen of thetarget vessel without the second conduit portion contacting the entirecircumference of the inner vessel wall.
 47. The device of claim 46,wherein the second conduit is generally semicircular in cross-section soas to leave the inner wall of the target vessel substantially uncovered.48. The device of claim 45, wherein at least one of the two free ends ofthe other leg of the T is expandable in an axial direction as well as aradial direction.
 49. The device of claim 45, wherein at least one ofthe two free ends of the other leg of the T has a shaped tip for smoothintroduction into the target vessel.
 50. The device of claim 43, whereinthe first conduit portion has a length in the range of from about 30 mmto about 50 mm, while the second conduit portion has a length in therange of from about 3 mm to about 20 mm.
 51. A device for delivering aconduit configured to be placed in fluid communication with a targetvessel and a source of blood, the device comprising: a support shafthaving a length; a sheath having a length, a lumen, and a wall with atleast one opening extending into the lumen; wherein the support shaft issized and configured to be at least partially positioned in the sheathlumen so as to contact the sheath wall and substantially block theopening by preventing communication with the sheath lumen via theopening; and wherein the support shaft is movable within the sheathlumen to selectively block or unblock the opening in the sheath wall.52. The device of claim 51, wherein the support shaft is an obturatorhaving a size that permits the obturator to slide within the sheathlumen, and the sheath wall includes a plurality of openings.
 53. Thedevice of claim 51, wherein the sheath is sized and configured to bereceived in a portion of a conduit that is sized and configured to bereceived in a coronary vessel.
 54. In combination with a conduit for usein placing a target vessel in fluid communication with a source ofblood, a delivery device for deploying the conduit, the combinationcomprising: a conduit including first and second portions, wherein thefirst and second conduit portions each have an axis and a lumen throughwhich blood may flow, the axes of the first and second conduit portionsbeing transverse to each other; wherein the first conduit portionincludes at least one inlet configured to be placed in fluidcommunication with a heart chamber containing blood, and the secondconduit portion includes at least one outlet configured to be at leastpartially positioned within the lumen of a target vessel to deliverblood to the target vessel; a delivery device including a shaft with alumen and at least one opening extending into the lumen, wherein thesecond conduit portion is mounted on the shaft; wherein the shaftopening is movable into and out of alignment with the lumen of the firstconduit portion; and wherein the shaft opening is moved into alignmentwith the lumen of the first conduit portion to deliver blood from thefirst conduit portion to the shaft lumen.
 55. The combination of claim54, wherein the shaft is rotatable within the second conduit portion,and the conduit is generally T-shaped.
 56. The combination of claim 55,wherein the hollow shaft is a sheath, and further comprising anobturator rotatably positioned in the sheath.